[Qemu-devel] [RFC v2 7/8] hw: arm: virt: register reserved IOVA region

[Eric Auger <eric.auger@linaro.org>]

Registers a 16x64kB reserved iova region. Currently this iova
region is used by the host kernel to map host MSI controller frames
(GICv2m, GITS_TRANSLATER). The host kernel needs this iova window
since it cannot program the PCIe device with MSI frame physical
address (as opposed to x86) since the MSI write transactions go
through the IOMMU.

The reserved region is mapped on the platform bus.

Signed-off-by: Eric Auger <eric.auger@linaro.org>

---

RFC v1 -> RFC v2:
- use the platform bus to map the reserved iova region
---
 hw/arm/virt.c | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 3839c68..4b2a891 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -805,7 +805,7 @@ static void create_pcie_irq_map(const VirtBoardInfo *vbi, uint32_t gic_phandle,
 }
 
 static void create_pcie(const VirtBoardInfo *vbi, qemu_irq *pic,
-                        bool use_highmem)
+                        bool use_highmem, MemoryRegion **reserved_reg)
 {
     hwaddr base_mmio = vbi->memmap[VIRT_PCIE_MMIO].base;
     hwaddr size_mmio = vbi->memmap[VIRT_PCIE_MMIO].size;
@@ -920,10 +920,16 @@ static void create_pcie(const VirtBoardInfo *vbi, qemu_irq *pic,
     qemu_fdt_setprop_cell(vbi->fdt, nodename, "#interrupt-cells", 1);
     create_pcie_irq_map(vbi, vbi->gic_phandle, irq, nodename);
 
+    /* initialize the reserved iova region for MSI binding (16 x 64kb) */
+    *reserved_reg = g_new0(MemoryRegion, 1);
+    memory_region_init_reserved_iova(*reserved_reg, OBJECT(dev),
+                                     "reserved-iova",
+                                     0x100000, &error_fatal);
+
     g_free(nodename);
 }
 
-static void create_platform_bus(VirtBoardInfo *vbi, qemu_irq *pic)
+static PlatformBusDevice *create_platform_bus(VirtBoardInfo *vbi, qemu_irq *pic)
 {
     DeviceState *dev;
     SysBusDevice *s;
@@ -962,6 +968,7 @@ static void create_platform_bus(VirtBoardInfo *vbi, qemu_irq *pic)
     memory_region_add_subregion(sysmem,
                                 platform_bus_params.platform_bus_base,
                                 sysbus_mmio_get_region(s, 0));
+    return PLATFORM_BUS_DEVICE(dev);
 }
 
 static void *machvirt_dtb(const struct arm_boot_info *binfo, int *fdt_size)
@@ -1015,7 +1022,7 @@ static void machvirt_init(MachineState *machine)
     VirtMachineState *vms = VIRT_MACHINE(machine);
     qemu_irq pic[NUM_IRQS];
     MemoryRegion *sysmem = get_system_memory();
-    MemoryRegion *secure_sysmem = NULL;
+    MemoryRegion *secure_sysmem = NULL, *reserved_reg;
     int gic_version = vms->gic_version;
     int n, max_cpus;
     MemoryRegion *ram = g_new(MemoryRegion, 1);
@@ -1024,6 +1031,7 @@ static void machvirt_init(MachineState *machine)
     VirtGuestInfoState *guest_info_state = g_malloc0(sizeof *guest_info_state);
     VirtGuestInfo *guest_info = &guest_info_state->info;
     char **cpustr;
+    PlatformBusDevice *pbus;
 
     if (!cpu_model) {
         cpu_model = "cortex-a15";
@@ -1161,7 +1169,7 @@ static void machvirt_init(MachineState *machine)
 
     create_rtc(vbi, pic);
 
-    create_pcie(vbi, pic, vms->highmem);
+    create_pcie(vbi, pic, vms->highmem, &reserved_reg);
 
     create_gpio(vbi, pic);
 
@@ -1200,7 +1208,8 @@ static void machvirt_init(MachineState *machine)
      * another notifier is registered which adds platform bus nodes.
      * Notifiers are executed in registration reverse order.
      */
-    create_platform_bus(vbi, pic);
+    pbus = create_platform_bus(vbi, pic);
+    platform_bus_map_region(pbus, reserved_reg);
 }
 
 static bool virt_get_secure(Object *obj, Error **errp)
-- 
1.9.1